1. Field of the Invention
The present invention relates to a drive unit for a vehicle that delivers power output of an engine to an automatic transmission via a motor that includes a plurality of rotors.
2. Description of Related Art
A drive unit for a vehicle has been known that includes a compound motor having a winding rotor and a magnet rotor that can differentially rotate with each other and being provided with a stator on the outer side of the magnet rotor and that delivers power output of an engine to a transmission via the compound motor (Japanese Patent Application Publication No. 2009-274536 (JP 2009-274536 A)). The other prior art documents that relate to the present invention include Japanese Patent Application Publication No. 2011-25911 (JP 2011-25911 A), Japanese Patent Application Publication No. 2010-526710 (JP 2010-526710 A), and Japanese Patent Application Publication No. 2005-54938 (JP 2005-54938 A).
Various types of an automatic transmission have been developed for vehicles such as an automatic transmission of a planetary gear type (AT), a continuously variable transmission (CVT), an automated manual transmission (AMT), and a dual clutch transmission (DCT). The AMT has an advantage over the others in terms of power transmission efficiency due to the relatively small number of friction engagement elements such as a clutch and a brake.
When the AMT is installed in the drive unit for a vehicle, the AMT interposes a neutral state during changing of a shift speed, which leads to disconnection of torque transmission. In a unit disclosed in JP 2009-274536 A, the power output of an engine, which is routed through a compound motor, is delivered to an input shaft of a transmission.